huber



Feb. 7, 1956 A. .1. HUBER 2,734,108

IRON VANE ELECTRICAL INSTRUMENT Filed Feb. 11, 1954 2 Sheets-Sheet 1 148 ALFRED J. HUBER 20 INVENTOR.

Feb. 7, 1956 A. J. HUBER 2,734,108

IRON VANE ELECTRICAL INSTRUMENT Filed Feb. 11, 1954 2 Sheets-Sheet 2ALFRED J. HUBER IN VEN TOR.

United States Patent IRON VANE ELECTRICAL INSTRUMENT Alfred J. Huber,Elizabeth, N. J.

.Al'Febnlary 11, 1954, Serial No. 409,700

6 Claims. (Cl. 200-103) invention relates :to electrical instruments andvmoreparticularly :to an iron vane repulsion type instrument of improvedconstruction affording certain manufacturing and operating advantages.

.Instruments of the type contemplated by this invention respond tocurrent flowing in the field coil. Such current :flow induces likemagnetic .poles in a fixed iron wane and :an associated movable ironvane whereby the resulting repulsion effect imparts a rotary movement to:themouahle correspondence with the magnitude of the current flow. Oneproblem .associated with instruments of this class has :been to increasethe sensitivity of the 1-instrument without an attendant increase in theoverallsize of the instrument and the complexity of construc- Amobjectof this invention is the provision of an iron vane type of instrument of.smallsize, simple construction and rugged character and whichinstrument will possess a highcresponse sensitivity.

.An object :of this .inventionis the provision of an iron vane type ofinstrument comprising a field coil supported one hollow, flanged spool,a plurality of axially-disposed iron vanessecured in .fixed positionwithin the spool and .extending radially toward the spool axis, and aplurality of pivotallyemounted movable iron vanes operatively associatedwith the fixed vanes, said movable vanes being rotatable about the spoolaxis.

.An object of this invention is the provision of an iron vane type of.instrument comprising a hollow insulator spoolhaving anupper and lowerflange, a field coil carried by the spool, a pluralityof axiallydisposed iron wanes secured-to the inner wall of the spool, said vanesextending toward the. spool :axis, a corresponding pluralityofmovabletiron vanes symmetrically disposed about the spool axis andindividually co-acting with the fixed vanes when the field. coil isenergized, alined pivot posts carried by the movable vanes, pivot ipinsextending outwardly of the pivot posts, .a bearing carried by the lowerspool flange and supporting one pivot pin, a second bearing car-- niedbya bridge supported by the upper spool flange and cooperatiag-with-theother pivot pin, spring means normally biasing the movable vanes in agiven direction, and a movablearm secured. to one of said pivot posts.

An object. of this invention is the provision of a movable vane.structure for. a repulsion type instrument and comprising a-pair. ofthin, substantially-rectangular iron plates, eachplatebeing; providedwith a rectangular notch at: each.end-..andan axial slot extending fromone such notch to the center of. the plate, said plates being ofbilaterally-symmetrical form taken with respect to the longitudinalaxisand the formation of the identical plate being such thatwhen oneplate is reversed relative to the other the. plates can be assembled toform a structure having a cross shape. in transverse section.

These and other objects and advantages will become apparent from thefollowing description when taken with the. accompanying drawingsillustrating a particular embodimentof the invention. It will beunderstood that hi the drawings arefor purposes of description and arenot to be construed as defining the scope or limits of the invention,reference beinghad for the latter purpose to the appended claims.

In the drawings wherein like reference characters denote like parts inthe several views:

Figure 1 is a side view of an instrument made in accordance with thisinvention;

Figure 2 is a top view of such instrument;

Figure 3 is a transverse section taken along the .line A-A of Figure 1;

Figure 4 is an enlarged elevation View showing the construction of thetwo rectangular plates which made up the movable system;

Figure 5 is an isometric, exploded view showing the cross-shaped movablevanes, the upper and lower pivot posts, and the pivot pins which formthe axis about which the movable system rotates;

Figure 6 is an elevation showing the assembled movable system;

Figure 7 is an enlarged fragmentary view showing the assembly of themovable arm and biasing spring on the upper pivot post;

Figure 8 is a similar view showing the assembly 'of the upper bridge;

Figure 9 is a transverse section talten along the line B--B of Figure -lbut with the movable vanes removed;

Figure 10 is similar to Figure 3 and showing the addition of coverplates which serve as dust covers and as a closure for the spool tothereby increase the damping factor of the instrument.

Reference is now made to Figures 1 and 2. The field coil 10 is wound onan insulator spool having a bottom flange 11 and a top flange 12. Alower jewel screw 13 is threaded into a central hole provided in theflange 11 and is locked in relatively fixed position by a nut 14. Anupper jewel screw 15 is similarly carried by a bridge 16 that is securedto the diametrically-opposite posts 17 by the screws 18, said postshaving lower ends threaded into suitable holes provided in the upperflange 12. Altentatively, these posts may be molded as integral parts ofthe spool. A not 19 serves to lock the jewel screw in fixed position.The movable system of the instrument is pivotally supported by the jewelscrews 13, 15 as will be described in more detail hereinbelow. For themo ment attention is directed to the fact that the upper part of theinstrument movable system includes a pivot post 20 which carries a pivotpin for cooperation with the upper jewel screw 15 and which post isarranged to carry the spiral spring 21 and the movable arm 22. Thoseskilled in this art will understand that in the case of an indicatinginstrument the movable arm 22 may be a pointer adapted to cooperate witha suitably calibrated scale. However, the illustrated instrument is arelay and the movable arm 22 carries a small bushing 24 made of amaterial having good electrical qualities such as silver,platinum-iridium, etc. Upon otary movement of the movable system, thecontact 24 will engage a cooperating, similar contact 25 which lies inthe arcuate path of travel of the movable contact and is secured to anabutment supported on the bridge 16, as will be described morespecifically hereinbelow with reference to Figure 8.

The relative arrangement of the fixed and movable iron vanes isillustrated in Figure 3 which is a transverse sectional view taken alongthe line AA of Figure 1. Here are shown the top spool flange 12 and thebridgesupporting posts 17. The fixed magnetic system of the instrumentincludes four vanes 30, 31, 32, 33 which are made of thin iron sheet andwhich extend axially of the spool. These vanes are spaced apart 9Oangular degrees and each is secured in fixed position by having one longside thereof cemented within longitudinal slots avscnos formed in theinner wall of the tubular section of the spool. Alternatively, thesevanes may be directly molded in position when the spool is made by amolding operation. A better understanding of this arrangement will behad by reference to Figure 9 which is a cross-sectional view taken alongthe line B-B of Figure l and which view shows the wall 34 of the tubularportion of the spool. Referring again to Figure 3, the movable systemoi": the instrument comprises four, thin iron vanes 35, 36, 3'7, 38,which are pivotally mounted for rotation about the longitudinal axis ofthe spool. Those skilled in this art will understand that when a currentflows in the field coil the resulting magnetic lines of force willmagnetizc the iron vanes so as to provide similar magnetic poles on thefixed and movable vanes. Consequently, there is developed a repulsionforce tending to separate the movable vanes from the fixed vanes. Sincethe movable vanes are arranged for rotation about the spool axis suchrepulsion force results in an angular movement of the movable vanes.

Reference is now made to Figure 4 which is an elevation view showing thetwo, thin, soft-iron plates which, when assembled, form the four movablevanes of the instrument. Each of the plates 40, 40 are of identicalconfiguration, having longitudinally-alined, substantially rectangularnotches 42, 43, and 42, 43' formed at opposite ends. Further, each plateincludes a longitudinal slot 44, 44, extending from the respectivenotches 42, 42' to the center of the plate. These slots have a widthsubstantially equal to the thickness of the plate whereby when theplates are reversely disposed, as shown in Figure 4, they may beassembled to form a cross-like structure 45, as shown in Figure 5. It isapparent that the associated end surfaces of each plate will be in acommon plane when the longitudinal slots extend at least to the centerof the plates. The assembled plates are preferably set in an appropriatefixture to assure a mutually perpendicular orientation of the four vanes34, 35, 36 and 37. Even though the longitudinal slots have a width suchthat the two plates must be force-fitted together, it is desirable toapply suitable cement along the mutually-contacting edges of the platesto provide a rugged assembled unit. Attention is here directed to thefact that the notches formed in the edges of the plates form,effectively, receptacles 47, 48, for the circular pivot posts 20, 20 theefiective diameters of such receptacles corresponding to the outerdiameters of the pivot posts. While the vane structure 45' is retainedin a suitable fixture the pivot posts are assembled and cemented theretoas shown in Figure 6. Each of the pivot posts includes an axial boreinto which are driven the associated, pointed pivots 49, 50, said pivotsbeing precisely alined to form the axis of rotation of the movablesystem. It is well to here point out that the upper pivot post 20 issomewhat longer than the lower post 20 since the upper portion of theinstrument carries the movable arm and the spiral biasing spring therebyrequiring a spacing of the upper jewel screw from the upper spoolflange, as is apparent from a study of Figure 1. Also, the upper pivotpost 20 is provided with a reduced-diameter outer end 51 for purposesnow to be described.

Figure 7 is a fragmentary elevation, with parts in section, showing theupper portion of the movable system. In this view are shown the vanes35, 37 and 33, the upper pivot post 20 carrying the upper pivot 49, thespiral spring 21 having its inner end soldered to an abutment 53 and thecross arm 22 carrying the contact 24 at one end. As explained withreference to Figure 5, the pivot post 20 includes a reduced diameterouter end 51 pro viding a shoulder to support the cross arm 22 and thespring abutment 53. It may here be pointed out that the cross arm 22includes a central hub provided with a hole and that the tail and sidearms carry adjustable balance weights 54, see also Figure l, fordynamically balancing the entire movable system, all in accordance withconventional practice in this art. The cross arm and the abutment 53 aresecured in fixed position on the pivot post 22 by peening over the endof the post, as shown.

Reference is now made to Figure 8 which illustrates those parts whichare operatively associated with the movable system components shown inFigure 7. Here are shown the bridge 16 supported by and secured to theposts 17 by the screws 18. The upperjewel screw 15 extends through athreaded, central-hole in the bridge and has a length sufficient toextend upwardly beyond a stacked arrangement of parts necessary for theproper functioning of the instrument. The spring abutment 56 includes anupwardly directed outer end and a downwardly directed inner end to whichthe outer end of the spiral spring 21 is soldered, see Figure 7. A studyof Figures 7 and 8 will show that the movable contact 24 is inelectrical contact with the bridge 16 through the movable arm 22, springabutment 53, spring 21 and abutment 56. Thus, current can be directed tosuch movable contact by connecting a wire to either of thebridge-fastening screws 18. Alternatively, a flexible lead wire may besoldered to the outer end of the abutmeet 55. Disposed over the abutment56 is an insulator bushing 57 having a shank to accept the reverselybentcrank 58 and the entire stack is secured in relatively fixed position bymeans of the nut 19 and the spring washer 59. The nut 19 is threadedupon the jewel screw to the extent required to frictionally retain theabutment 56 and the crank 58 in any preset angular position duringnormal operations of the instrument. The inner, downwardly bent end ofthe crank has secured thereto, as by solder, the stationary relaycontact 25 (see also Figures 1 and 2) and it should be apparent that theposition of the contact 25 relative to the movable contact 24 can beadjusted upon rotation of the crank 58.'-Likewise, it is clear fromFigure 8 that the crank and the.con tact 25, are electrically isolatedfrom the entire movable system by the insulator bushing 57 and theinsulator washer 66. Consequently, an external circuit connected betweenthe bridge 16 and the crank 58 will be completed upon closure of therelay contacts 24, 25. The point of closure of the relay contacts can beadjusted by rotation of the crank to set the relatively stationarycontact 25 at a desired angular position relative to the zero positionof the instrument movable system. Further, the zero position, and thesensitivity of the instrument can be adjusted by rotation of theabutment 56 which controls the angular orientation of the biasing spring21.

It is pointed out that the movable vanes of the instru' ment aredisposed entirely within the tubular portion of the spool carrying thefield coil. This feature facilitates the provision of a closed chamberto serve as a means for damping the rotation of the movable system.Figure 10 is similar to Figure 3 and shows the addition of two, similarflat plates 63, 64 of generally semi-circular configuration. Each of theplates is pivotally attached to one of the bridge-supporting posts 17.When theplates are moved to the closed position, as is the plate 63,there is formed a substantially circular plate which closes the upperopening of the spool except for the central aperture formed by reason ofthe step-like complementary plate edges, which aperture clears the upperpivot post 20. By so confining the air within the spool chamber, 1provide a practical degree of air damping for the instrua ment and, atthe same time, protect the interior of the instrument against theentrance of foreign matter which may interfere with instrumentoperation.

The above-described instrument may be housed in a suitable case as, forexample, a hermetically sealed can provided with conventionalsolder-sealed or pin-type terminals to which the ends of thefield coiland the relay contacts are connected.

Having now described my invention in detail in ac cordance with therequirements of the patent statutes,

those skilled in this art will find no difiiculty in making changes andmodifications in the illustrated instrument construction to meetspecific requirements. Such changes and modifications may be madewithout departing from the scope and spirit of the invention as setforth in the following claims.

I claim:

1. An electrical instrument comprising an insulator spool having anupper and a lower flange joined by a hollow tube; a field coilencircling the tube; a fixed iron vane system including foursubstantially-rectangular, soft-iron vanes longitudinally disposedwithin the tube and extending substantially the full axial extent of thefield coil, each vane extending inwardly of the tube and having a longside disposed within a longitudinal groove formed in the inner wall ofthe tube; a movable system comprising two flat sheets of soft ironsecured together so as to form four substantially-rectangular, soft-ironvanes disposed in mutually perpendicular planes, said vanes having anaxial length substantially equal to that of the fixed vanes; alinedpivot posts secured at opposite ends of the movable system vanes, eachpost carrying a pivot; a bearing carried by the lower spool flange andcooperating with one of the pivots; a bearing carried by a bridge membersupported by the upper spool flange and cooperating with the otherpivot; and spring means secured to the movable system and normallybiasing same in a direction to bring the movable vanes proximate to thefixed vanes.

2. The invention as recited in claim 1 wherein the movable system vanesare provided with end notches which are symmetrical with respect to theaxis formed by the pivot pins, and the pivot posts are partiallydisposed within such notches.

3. The invention as recited in claim 1, in combination with a pair offlat plates each pivotally attached to posts supporting the bridgemember from the upper spool flange, said plates being pivotally slidablealong the outer 6 surfaces of the upper spool flange to form a closurefor the said tube.

4. The invention as recited in claim 1, including a movable contactmember secured to the movable system and a cooperating contact memberpivotally supported on said bridge member, said cooperating memberextending into the arcuate path of travel of said movable contactmember; and means electrically isolating the cooperating contact memberfrom the bridge member.

5. A movable iron vane system for an electrical instrument comprising apair of thin, rectangular, soft-iron plates, each plate having asubstantially-rectangular central notch formed in each end and includinga central, longitudinal slot extending from one such notch to at leastthe center of the plate, said plates being reversely disposed relativeto each other and in perpendicular planes so that the ends thereof areco-planar, a circular pivot post seated in the cooperating notches atthe plate ends and secured to the side walls defining such cooperatingplate notches, and alined pivot pins extending from said pivot posts.

6. The invention as recited in claim 5, wherein one of said pivot postsincludes a reduced-diameter outer portion, a movable arm having a hubsection provided with a hole and disposed over said outer portion of thepivot post; and a spring abutment having a hole and disposed over theouter portion of the pivot post, the free end of said outer post portionbeing upset to secure the movable arm and abutment to the pivot post.

References Cited in the file of this patent UNITED STATES PATENTS409,207 Knowles Aug. 20, 1889 1,842,345 Eaton Jan. 19, 1932 1,866,436Weston July 5, 1932 2,398,651 Lamb Apr. 16, 1946 2,546,284 WeisbeckerMar. 27, 1951

